PCM5102, 2VRMS ground centered direct output with two digital filters - Page 9 - diyAudio
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Old 30th July 2013, 04:58 PM   #81
Rochey is offline Rochey  United States
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Hello Folks,

I'm the Audio Systems engineer that defined this part. I haven't had the opportunity to go through all 8 pages of this thread quite yet. (I'm hoping there isn't too much flaming... this part is my baby!)

If any of you have any questions on how to use the part, or configure it, or any other system level questions I will my best to stop by this thread from time to time. However, the main portal for tech support on these parts is over at TI's e2e forum (TI E2E Community)

Sorry Mod, I'm not trying to steal traffic from this place, just trying to show people where they can get more data and help with these parts. -- Keep up the good work!

Many thanks,

Dafydd Roche
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Old 1st August 2013, 12:01 AM   #82
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Quote:
Originally Posted by Rochey View Post
Hello Folks,

I'm the Audio Systems engineer that defined this part. I haven't had the opportunity to go through all 8 pages of this thread quite yet. (I'm hoping there isn't too much flaming... this part is my baby!)

If any of you have any questions on how to use the part, or configure it, or any other system level questions I will my best to stop by this thread from time to time. However, the main portal for tech support on these parts is over at TI's e2e forum (TI E2E Community)

Many thanks,

Dafydd Roche
Hi, Dafydd,

Because of your audio DAC product definition role, I would like to ask if you have any information you might share about whether other T.I. audio DACs (such as in the PCM179x series) will incorporate both minimum phase and linear phase digital interpolation filter impulse/phase responses, such as in your PCM5102?

In addition, may I suggest that it would be highly desireable for the DAC's embedded digital interpolation filter to support a sharply bandimited (non half-band) implementation. Meaning, where the filter frequency response is fully in to the stop-band by the Nyquist frequency (22.05KHz for CD), yet is flat to within a few tenths of a decibel at 20.0KHz. The digital audio industry generically refers to such a filter response as, 'apodizing'.

Thank you.
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Old 1st August 2013, 05:20 AM   #83
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hi,

would you be willing to comment on this post:

PCM5102, 2VRMS ground centered direct output with two digital filters - Page 5 - diyAudio

I built a proto (a while back) and gave up after hearing a harsh clipping sound as the level reached near 0db. some people have said that its a Gibbs-based problem.

I'd love to hear the designer's comments about this issue.
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Old 17th September 2013, 07:29 PM   #84
usul27 is offline usul27  Switzerland
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Do you run your PCM5102 from the same 3.3V power supply for both digital and analog? Started designing a sound interface for the Raspberry Pi based on the chip. The idea is to generate a clean 3.3V analog supply from the 5V line. From this thread I guess, I should go up to 3.5-3.6V. Any comments on this?
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Old 18th September 2013, 03:17 PM   #85
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Originally Posted by usul27 View Post
Do you run your PCM5102 from the same 3.3V power supply for both digital and analog? Started designing a sound interface for the Raspberry Pi based on the chip. The idea is to generate a clean 3.3V analog supply from the 5V line. From this thread I guess, I should go up to 3.5-3.6V. Any comments on this?
I didn't try this specific dac in 3.6V modus, but I can't imagine the difference is that large. I do have experience with direct I2S audio from the Raspberry Pi, and it's not easy to get it to a acceptable level.

For you, it's much more important to keep the noise from the Pi away from the DAC chip.

So it's wise to separate the supply of the Pi and the DAC. Don't take a 5V from the Pi and regulate it down, but take a separate 5V source to regulate down. Make sure the 5V for the Pi is also of high quality, this helps to get the I2S signal clean.

The I2S output header of the Pi is directly connected to the Proc, impedance mismatch problems can cause a lot of trouble.

Clock quality is very low, give the DAC it's dedicated XO.
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